The recent emergence of women-only substance abuse treatment programs reflects the recognition that traditional mixed-gender programs often fail to address women's needs, and programs designed specifically for parenting women have been developed to address the additional needs faced by mothers and their children. Yet little research has been conducted to assess the ways in which programs designed specifically for women differ from traditional mixed-gender programs or whether women-only programs produce better treatment outcomes. While there are a handful of small-scale studies that look at policy-relevant client outcomes, and some larger-scale studies that look at program costs or retention, there are still no large-scale comparative studies that demonstrate: 1) whether specialized programs that address parenting women's needs yield better outcomes than more traditional approaches, 2) what program characteristics are associated with successful outcomes (best practices), and 3) whether these outcomes offset the costs of providing the specialized services. The proposed study addresses that gap. The specific aims are: 1) to determine whether specialized long-term residential treatment programs for parenting women are more effective than traditional mixed gender long-term residential programs in producing desired outcomes for women and children, 2) to determine what program characteristics are most associated with successful client outcomes (best practices), and 3) assess whether the reduction in public sector costs from achieving desired outcomes offset the additional costs of specialized programming. The study will be accomplished through a retrospective quasi-experimental outcome evaluation of specialized long-term residential treatment for women with children in Washington State. The data will include 697 women with children aged 1 through 6 who have been admitted to the specialized treatment sites from 1994 to the present, and a comparison sample of 751 who have been admitted to standard mixed-gender long-term residential sites. Outcomes will be gathered from administrative data sources on each client for 4 years post-admission, and modeled as a function of: 1) differential effectiveness of the specialized and non-specialized modalities, 2) site-level program variation, 3) variation in baseline characteristics or "casemix," and 4) macro-level trends that potentially affect specialized and non-specialized clients differentially. Propensity score technology will be used to minimize bias from pre-existing differences between groups, and effects will be estimated with a 3-level mixed-effects regression model to capture both longitudinal and within-site clustering. All outcomes will be monetized to enable re-expression of net program effects as costs or savings to government.